1. Field of the Invention
The present invention relates to a method and apparatus for forming a cylindrical member by winding a belt-shaped member around an outer periphery of a forming drum and by causing leading and trailing ends thereof to butt against each other.
2. Description of the Related Art
As a conventional method and apparatus for forming a cylindrical member, for example, one disclosed in Japanese Patent Application Laid-Open No. 97532/1991 is known. This apparatus includes: a forming drum having a cylindrical unit formed with a slit extending substantially in an axial direction of the cylindrical unit and around which a belt-shaped member is wound wherein a slight clearance between both ends of the belt-shaped member is aligned with the slit; a first joining unit arranged in the forming drum in face-to-face relation with the slit; and a second joining unit arranged on an outer side of the forming drum and movable toward and away from the first joining unit., wherein the second joining unit in cooperation with the first joining unit pulls closer together and butt joins the ends of the belt-shaped member wound around the forming drum when the ends of the belt-shaped member are aligned with the slit.
With the above-described conventional method and apparatus for forming a cylindrical member, no problem is presented when only one belt-shaped member is wound directly around the forming drum. However, if an attempt is made to join the ends of another belt-shaped member by winding it around a belt-shaped member already wound around the forming drum, portions of the lower belt-shaped member already wound, together with the upper belt-shaped member, are pulled closer by the first and second joining units, so that the formation of such a cylindrical member cannot be effected.